Incremento en biomasa y supervivencia de una plantación de Pinus hartwegii Lindl. en áreas quemadas

in the year 2002 prescribed fire treatments were applied on open pinus hartwegii lindl., forests in the ajusco volcano, south of mexico city, mexico. the treatments consisted of two fire-intensities: high and low, and two seasons of fire application: march and may, plus an unburned control (one per season). in july of the same year were planted 420 seedlings of two size categories (big and small). in this work were evaluated the survival and biomass increment of such trees three years after plantation establishment. it was recorded the survival in all of the forest plantation and a 30 trees sample was gathered to determine biomass. the mortality probability was estimated with a logistic model. the analysis of variance and the least significant difference test were utilized for the other variables. the probability of mortality of the trees in the control did not show differences with the trees in the may burns, but it was lower than that of the march burns. such response in the march treatments was adduced to the earlier competition, for the competition in the forest plantation was not eliminated, also to a higher understory cover and to a lesser abundance of nurse shrubs. there was no effect of treatments on tree growth. the total biomass increment was equal to 8.5 g·yr-1.